A team of researchers at Johns Hopkins University has made a detailed study of the wake effects caused by airflow both within and around a wind farm. (Photo: Photo courtesy of Shutterstock)

The use of wind power as a major source of energy has expanded tremendously over the past few years. The need to use this clean and renewable energy source has prompted the design of advanced wind farms where careful consideration is given to the spacing and alignment of the turbines, so that they work efficiently and reduce any "wake effects", where the motion of one turbine impacts the natural wind flow to adjacent downwind turbines effectively causing them to experience diminished energy production.

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In order to fully harness their potential, wind turbines must be spaced optimally so that they can capture more wind, produce more energy, and be profitable for the farm. To do this, turbine manufacturers use simple computer models and come with the most ideal arrangement for the turbines where clockwise rotating fans are alternated with counterclockwise fans in a checkerboard pattern. This pattern is believed to produce the highest power output and although it works well for small wind farms, when applied to larger wind-farms, it is difficult to predict its accuracy due to the wake-effect.

According to a press release Tuesday, to get around this problem, a team of researchers at Johns Hopkins University (JHU) has made a detailed study of the wake effects caused by airflow both within and around a wind farm. Their study provides insight into factors that determine the most favorable positioning and is an alternative to the checkerboard pattern. Their work has been published in the Journal of Renewable and Sustainable Energy, produced by AIP Publishing.

Their research is a huge step forward in creating new design concepts for turbine farms that will maximize power output in places with strong winds.

"It's important to consider these configurations in test cases," said Richard Stevens, who conducted the research with Charles Meneveau and Dennice Gayme at JHU. "If turbines are built in a non-optimal arrangement, the amount of electricity produced would be less and so would the revenue of the wind farm."

Wind farms are designed by taken into account the landscape, weather patterns, and other socio-political considerations. Designs may vary depending on whether the land is hilly or flat and the pattern of wind through the year.

Common test cases to study wind-farm behavior are wind farms in which turbines are either installed in rows, which will be aligned against the dominant winds, or in staggered, checkerboard-style blocks where every second row is staggered so that the turbines peek out between the gaps in the previous row.

Staggering is shown to improve the capacity of the farms and produce more energy in a smaller

footprint. But in their new study Stevens and his team improvised the checkerboard design.

Specifically, they found that better power output may be obtained through an "intermediate" staggering, where each row is imperfectly offset -- like a checkerboard that has slipped slightly out of whack.